Which undercoat plaster?

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Hello

I will be repairing some blown areas of plaster in my hallway. I intend to knock off the affected plaster back to brick and patch it up. I've read about different undercoat plasters but I'm not entirely sure whether to use browning, bonding or hardwall. Also do I have to pva the bricks before applying the undercoat? Then after that I know to use multi-finish for the final coat :)

Thanks

Phil
 
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Some extra information will help your feedback -
1) how old is the house?
2) Does the wall have a cavity?

Gypsum plasters are not a one-size-fits-all.

If you can post a pic, it may help too.
 
Hello

1. The house was built in the 1950's

2. Yes it does have a cavity which is insulated.

Phil
 
Hello

1. The house was built in the 1950's

2. Yes it does have a cavity which is insulated.

Phil

Ok, fairly modern so probably ok with them.
If it was me, would go for hardwall then. As it is a hall there is more potential for through traffic and the odd knock. Hardwall has a slightly better impact resistance.
Usual stuff - diluted PVA:water 1:4 or 1:5 on the night before and just before you fill with hardwall (when it's tacky). Build up in layers so you don't get it slumping.

There is some other preparation that can help - for example I neaten the edges a bit with a stanley knife and actually cut the plaster edge angled slightly so is easier to work the plaster into the join. Also pay special attention to applying PVA at the join. Especially if the existing is crumbly.

Thinking out loud - you probably need to be aware though that if there are patches that are loosening, satisfy yourself that the remainder really is sound. If the whole lot is struggling, can look at taking the hit now and replacing all. This may open drylining with p/board as an option too then.
If you get the remainder of the undercoat loosening in a year or two, you won't be happy. Though some new plaster in the wall, will probably help secure the other bits - but no guarantees!

Assuming you do patch - also apply scrim tape over the joins with the original before you skim to help strengthen, as expansion may be different due to different materials.

That's all I can think of for now.
 
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Patching is often done wrong. If you apply hardwall or what ever you plan to use, to the area you should then rule off with a stright edge and when it has set firm but not hard you should scrape out a couple of mm, then when dry apply skim, rule off the skim and trowel up taking care with the edge. just keep the edge wet with a brush. this way you will get a good patch.
 
Hi, I'm doing exactly the same as the op tomorrow, planning on using Browning though is that ok?
It will be going to brick.
Also how long after pva'ing can I put the Browning on?
Any help much appreciated.
 
Hi, I'm doing exactly the same as the op tomorrow, planning on using Browning though is that ok?
It will be going to brick.
Also how long after pva'ing can I put the Browning on?
Any help much appreciated.

Prob should have started another thread - but as only a couple of questions...

Browning probably fine. Only played with Bonding and Hardwall simply because availability seems less on Browning. If you check the BG website (link in wiki), there is info on each which tells you what they are intended for.

You know when to apply when the PVAed wall feels tacky to the touch. No hard and fast timings - experience!

Peaps - good tip, thanks. Was expecting OP to reskim entire wall, but I guess comes down to skill and may be applying multi to the patches only.
 
Hi, I'm doing exactly the same as the op tomorrow, planning on using Browning though is that ok?
It will be going to brick.
Also how long after pva'ing can I put the Browning on?
Any help much appreciated.

Prob should have started another thread - but as only a couple of questions...

Browning probably fine. Only played with Bonding and Hardwall simply because availability seems less on Browning. If you check the BG website (link in wiki), there is info on each which tells you what they are intended for.

You know when to apply when the PVAed wall feels tacky to the touch. No hard and fast timings - experience!

Peaps - good tip, thanks. Was expecting OP to reskim entire wall, but I guess comes down to skill and may be applying multi to the patches only.

You can mix 50/50 sand and thistle plaster for a backing then skim. Goes off quicker as well... I keep out of date plaster just for the job.
 
Thanks people.
How hard is it plastering a ceiling compared to walls ? I've only ever done some plastering on walls but not sure whether to do my ceiling.
It's got a very small profile artex on at the moment. If I did do it I take it just do the usual pva ?
 
[Ok, fairly modern so probably ok with them.
If it was me, would go for hardwall then. As it is a hall there is more potential for through traffic and the odd knock. Hardwall has a slightly better impact resistance.
Usual stuff - diluted PVA:water 1:4 or 1:5 on the night before
hi newb i wouldent use pva with hardwall, hardwall needs a bit of suction to hold it to the wall, if you use pva it could cause the hardwall to delaminate
if hes just patching he could use a bit of pva and thistle bonding
 
Thanks people.
How hard is it plastering a ceiling compared to walls ? I've only ever done some plastering on walls but not sure whether to do my ceiling.
It's got a very small profile artex on at the moment. If I did do it I take it just do the usual pva ?
you just have to think "wall", and do it exactly the same , it takes some getting used to, but after doing a few of them it becomes easy, google typewriter method, also you could use pva but you will be far better off using a bonding agent such as bondit bluegrit or wba
 

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